The Scientific Committee on Consumer Safety (SCCS) has recently determined that hydroxyapatite (HAP) in nanoform is safe for use in oral care products, with concentrations up to 29.5% in toothpaste and 10% in mouthwash. New safety showed that HAP nano does not cause genetic mutations, cytotoxicity, or inflammation, and is not significantly taken up by cells. The safety assessment applies only to specific types of HAP nanoparticles that meet certain criteria, such as rod-shaped particles with specific length-to-width ratios and no surface modifications. The case demonstrates that high-quality in vitro safety data can increase the possibilities of safely marketing nanomaterials. 

Use of hydroxyapatite in nano-form in oral care products is considered safe

The Scientific Committee on Consumer Safety (SCCS) has determined in June 2025 that hydroxyapatite in nanoform (HAP nano) is safe for use in oral care products. Specifically, it can be used at concentrations up to 29.5% in toothpaste and up to 10% in mouthwash. HAP is a mineral that naturally occurs in tooth enamel and bone. In its nanoform, HAP is added to toothpaste and mouthwash to help restore lost minerals and to rebuild and strengthen tooth enamel. 

The European Union (EU) requires that any materials in nanoform used in personal care products is reported on the ingredient list before they can be sold. Experts from the SCCS, which is an advisory body of the European Commission, evaluate these materials for safety. The SCCS’s latest conclusion on HAP nano comes after the SCCS’s fourth review. Earlier assessments by the SCCS were inconclusive regarding the safety of HAP nano at a maximum concentration of 10%, primarily due to concerns about potential DNA damage by the rod-shaped particles. 

The new evidence provided by industry

In 2022, companies provided new safety data on HAP nano used in oral care products. This data shows that HAP nano does not cause genetic mutations in various in vitro tests conducted under Good Laboratory Practice (GLP) conditions and in accordance with OECD guidelines. It seems that the cells do not significantly take up the HAP nanoparticles. 

The data also showed that HAP nano does not cause cytotoxicity or inflammation, even at high concentrations in two cell models representing the mouth mucosa. The mouth mucosa likely does not absorb HAP nanoparticles in significant amounts. Additionally, the epithelial cells in the mouth continuously renew themselves, meaning that any cells that may have taken up these particles will eventually be replaced. Moreover, HAP nanoparticles that have been unintentionally swallowed while using oral care products will rapidly dissolve in the acidic environment of the stomach into calcium and phosphate ions, which are naturally found in various food sources such as milk. This eliminates any nano-specific safety concerns.

HAP nano particle criteria

The conclusions of the safety of HAP nano at concentrations up to 29.5% in toothpaste and up to 10% in mouthwash are only valid for the type of HAP nanoparticles that the SCCS assessed. This refers specifically to rod-shaped HAP nanoparticles, with at least 87% (based on particle number) having a length-to-width ratio of 3 or less, and the remaining 13% should not exceed a length that is more than nine times longer than their width. In addition, the HAP nanoparticles should not be coated or surface-modified. Any HAP nanoparticles that do not meet these criteria will require a separate safety assessment.

Reflection by RIVM

The case of HAP nano demonstrates that it is worthwhile for industry to provide additional high-quality in vitro safety data, in addition to the existing data for HAP nano. Based on this extra information, HAP nano was found to be safe for use in higher amounts in toothpaste and mouthwash than previously allowed. This additional assessment was conducted in accordance with EU European Union (European Union ) cosmetics regulations, which means no animal testing was involved. 

Most of the in vitro models that were used were validated OECD testing methods, except for the mouth mucosa models. The model with the stratum corneum simulates the outer cell layer of the human gums, while the model without the stratum corneum resembles the mucosa of the oral cavity. These models are commercially available and are often produced under controlled conditions to ensure consistency and meet quality standards. Without these supportive tests, industry would not have been allowed to market oral care products containing these specific HAP nano particles at these higher concentrations.